Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 1 | /* Find debugging and symbol information for a module in libdwfl. |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 2 | Copyright (C) 2006-2014 Red Hat, Inc. |
| 3 | This file is part of elfutils. |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 4 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 5 | This file is free software; you can redistribute it and/or modify |
| 6 | it under the terms of either |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 7 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 8 | * the GNU Lesser General Public License as published by the Free |
| 9 | Software Foundation; either version 3 of the License, or (at |
| 10 | your option) any later version |
| 11 | |
| 12 | or |
| 13 | |
| 14 | * the GNU General Public License as published by the Free |
| 15 | Software Foundation; either version 2 of the License, or (at |
| 16 | your option) any later version |
| 17 | |
| 18 | or both in parallel, as here. |
| 19 | |
| 20 | elfutils is distributed in the hope that it will be useful, but |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 21 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 22 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 23 | General Public License for more details. |
| 24 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 25 | You should have received copies of the GNU General Public License and |
| 26 | the GNU Lesser General Public License along with this program. If |
| 27 | not, see <http://www.gnu.org/licenses/>. */ |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 28 | |
| 29 | #include "libdwflP.h" |
| 30 | |
| 31 | const char * |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 32 | internal_function |
| 33 | __libdwfl_getsym (Dwfl_Module *mod, int ndx, GElf_Sym *sym, GElf_Addr *addr, |
| 34 | GElf_Word *shndxp, Elf **elfp, Dwarf_Addr *biasp, |
| 35 | bool *resolved, bool adjust_st_value) |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 36 | { |
| 37 | if (unlikely (mod == NULL)) |
| 38 | return NULL; |
| 39 | |
| 40 | if (unlikely (mod->symdata == NULL)) |
| 41 | { |
| 42 | int result = INTUSE(dwfl_module_getsymtab) (mod); |
| 43 | if (result < 0) |
| 44 | return NULL; |
| 45 | } |
| 46 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 47 | /* All local symbols should come before all global symbols. If we |
| 48 | have an auxiliary table make sure all the main locals come first, |
| 49 | then all aux locals, then all main globals and finally all aux globals. |
| 50 | And skip the auxiliary table zero undefined entry. */ |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 51 | GElf_Word shndx; |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 52 | int tndx = ndx; |
| 53 | int skip_aux_zero = (mod->syments > 0 && mod->aux_syments > 0) ? 1 : 0; |
| 54 | Elf *elf; |
| 55 | Elf_Data *symdata; |
| 56 | Elf_Data *symxndxdata; |
| 57 | Elf_Data *symstrdata; |
| 58 | if (mod->aux_symdata == NULL |
| 59 | || ndx < mod->first_global) |
| 60 | { |
| 61 | /* main symbol table (locals). */ |
| 62 | tndx = ndx; |
| 63 | elf = mod->symfile->elf; |
| 64 | symdata = mod->symdata; |
| 65 | symxndxdata = mod->symxndxdata; |
| 66 | symstrdata = mod->symstrdata; |
| 67 | } |
| 68 | else if (ndx < mod->first_global + mod->aux_first_global - skip_aux_zero) |
| 69 | { |
| 70 | /* aux symbol table (locals). */ |
| 71 | tndx = ndx - mod->first_global + skip_aux_zero; |
| 72 | elf = mod->aux_sym.elf; |
| 73 | symdata = mod->aux_symdata; |
| 74 | symxndxdata = mod->aux_symxndxdata; |
| 75 | symstrdata = mod->aux_symstrdata; |
| 76 | } |
| 77 | else if ((size_t) ndx < mod->syments + mod->aux_first_global - skip_aux_zero) |
| 78 | { |
| 79 | /* main symbol table (globals). */ |
| 80 | tndx = ndx - mod->aux_first_global + skip_aux_zero; |
| 81 | elf = mod->symfile->elf; |
| 82 | symdata = mod->symdata; |
| 83 | symxndxdata = mod->symxndxdata; |
| 84 | symstrdata = mod->symstrdata; |
| 85 | } |
| 86 | else |
| 87 | { |
| 88 | /* aux symbol table (globals). */ |
| 89 | tndx = ndx - mod->syments + skip_aux_zero; |
| 90 | elf = mod->aux_sym.elf; |
| 91 | symdata = mod->aux_symdata; |
| 92 | symxndxdata = mod->aux_symxndxdata; |
| 93 | symstrdata = mod->aux_symstrdata; |
| 94 | } |
| 95 | sym = gelf_getsymshndx (symdata, symxndxdata, tndx, sym, &shndx); |
| 96 | |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 97 | if (unlikely (sym == NULL)) |
| 98 | { |
| 99 | __libdwfl_seterrno (DWFL_E_LIBELF); |
| 100 | return NULL; |
| 101 | } |
| 102 | |
| 103 | if (sym->st_shndx != SHN_XINDEX) |
| 104 | shndx = sym->st_shndx; |
| 105 | |
| 106 | /* Figure out whether this symbol points into an SHF_ALLOC section. */ |
| 107 | bool alloc = true; |
| 108 | if ((shndxp != NULL || mod->e_type != ET_REL) |
| 109 | && (sym->st_shndx == SHN_XINDEX |
| 110 | || (sym->st_shndx < SHN_LORESERVE && sym->st_shndx != SHN_UNDEF))) |
| 111 | { |
| 112 | GElf_Shdr shdr_mem; |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 113 | GElf_Shdr *shdr = gelf_getshdr (elf_getscn (elf, shndx), &shdr_mem); |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 114 | alloc = unlikely (shdr == NULL) || (shdr->sh_flags & SHF_ALLOC); |
| 115 | } |
| 116 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 117 | /* In case of an value in an allocated section the main Elf Ebl |
| 118 | might know where the real value is (e.g. for function |
| 119 | descriptors). */ |
| 120 | |
| 121 | char *ident; |
| 122 | GElf_Addr st_value = sym->st_value & ebl_func_addr_mask (mod->ebl); |
| 123 | *resolved = false; |
| 124 | if (! adjust_st_value && mod->e_type != ET_REL && alloc |
| 125 | && (GELF_ST_TYPE (sym->st_info) == STT_FUNC |
| 126 | || (GELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC |
| 127 | && (ident = elf_getident (elf, NULL)) != NULL |
| 128 | && ident[EI_OSABI] == ELFOSABI_LINUX))) |
| 129 | { |
| 130 | if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR)) |
| 131 | { |
| 132 | if (elf != mod->main.elf) |
| 133 | { |
| 134 | st_value = dwfl_adjusted_st_value (mod, elf, st_value); |
| 135 | st_value = dwfl_deadjust_st_value (mod, mod->main.elf, st_value); |
| 136 | } |
| 137 | |
| 138 | *resolved = ebl_resolve_sym_value (mod->ebl, &st_value); |
| 139 | if (! *resolved) |
| 140 | st_value = sym->st_value; |
| 141 | } |
| 142 | } |
| 143 | |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 144 | if (shndxp != NULL) |
| 145 | /* Yield -1 in case of a non-SHF_ALLOC section. */ |
| 146 | *shndxp = alloc ? shndx : (GElf_Word) -1; |
| 147 | |
| 148 | switch (sym->st_shndx) |
| 149 | { |
| 150 | case SHN_ABS: /* XXX sometimes should use bias?? */ |
| 151 | case SHN_UNDEF: |
| 152 | case SHN_COMMON: |
| 153 | break; |
| 154 | |
| 155 | default: |
| 156 | if (mod->e_type == ET_REL) |
| 157 | { |
| 158 | /* In an ET_REL file, the symbol table values are relative |
| 159 | to the section, not to the module's load base. */ |
| 160 | size_t symshstrndx = SHN_UNDEF; |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 161 | Dwfl_Error result = __libdwfl_relocate_value (mod, elf, |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 162 | &symshstrndx, |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 163 | shndx, &st_value); |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 164 | if (unlikely (result != DWFL_E_NOERROR)) |
| 165 | { |
| 166 | __libdwfl_seterrno (result); |
| 167 | return NULL; |
| 168 | } |
| 169 | } |
| 170 | else if (alloc) |
| 171 | /* Apply the bias to the symbol value. */ |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 172 | st_value = dwfl_adjusted_st_value (mod, |
| 173 | *resolved ? mod->main.elf : elf, |
| 174 | st_value); |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 175 | break; |
| 176 | } |
| 177 | |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 178 | if (adjust_st_value) |
| 179 | sym->st_value = st_value; |
| 180 | |
| 181 | if (addr != NULL) |
| 182 | *addr = st_value; |
| 183 | |
| 184 | if (unlikely (sym->st_name >= symstrdata->d_size)) |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 185 | { |
| 186 | __libdwfl_seterrno (DWFL_E_BADSTROFF); |
| 187 | return NULL; |
| 188 | } |
Elliott Hughes | 0333382 | 2015-02-18 22:19:45 -0800 | [diff] [blame] | 189 | if (elfp) |
| 190 | *elfp = elf; |
| 191 | if (biasp) |
| 192 | *biasp = dwfl_adjusted_st_value (mod, elf, 0); |
| 193 | return (const char *) symstrdata->d_buf + sym->st_name; |
| 194 | } |
| 195 | |
| 196 | const char * |
| 197 | dwfl_module_getsym_info (Dwfl_Module *mod, int ndx, |
| 198 | GElf_Sym *sym, GElf_Addr *addr, |
| 199 | GElf_Word *shndxp, |
| 200 | Elf **elfp, Dwarf_Addr *bias) |
| 201 | { |
| 202 | bool resolved; |
| 203 | return __libdwfl_getsym (mod, ndx, sym, addr, shndxp, elfp, bias, |
| 204 | &resolved, false); |
| 205 | } |
| 206 | INTDEF (dwfl_module_getsym_info) |
| 207 | |
| 208 | const char * |
| 209 | dwfl_module_getsym (Dwfl_Module *mod, int ndx, |
| 210 | GElf_Sym *sym, GElf_Word *shndxp) |
| 211 | { |
| 212 | bool resolved; |
| 213 | return __libdwfl_getsym (mod, ndx, sym, NULL, shndxp, NULL, NULL, |
| 214 | &resolved, true); |
Ben Cheng | 25b3c04 | 2013-11-20 14:45:36 -0800 | [diff] [blame] | 215 | } |
| 216 | INTDEF (dwfl_module_getsym) |